Nico Arbeck, Head of Department Material Use at C.A.R.M.E.N. e.V.

Read below a guest article by Nico Arbeck, Head of Department Material Use at C.A.R.M.E.N. e.V.

Final report available

Together with nine partners, C.A.R.M.E.N. e.V. carried out the model project “Practical test of compostable bags – circular economy with compostable fruit and vegetable bags” from December 2020 to February 2022. The project was funded by the Bavarian Ministry of Economic Affairs, Regional Development and Energy as part of the bioeconomy strategy “Zukunft.Bioökonomie.Bayern”. The strategy includes an action plan with a series of 50 different measures, and the practical test of the compostable bags is the first one that has already been completed.

With this strategy Bavaria is taking its first major step toward a new economic system. It is based on biogenic, renewable resources instead of fossil, finite resources and is oriented toward natural material cycles. The focus is on resource efficiency and sustainability. The aim is to meet global challenges such as climate change, environmental pollution, and dwindling fossil resources as well as to transform Bavaria into a sustainable business and agricultural location fit for the future. Innovative, bio-based and compostable plastic products (= compostable materials) can contribute to this, as they use biogenic raw materials and increase the circular economy and sustainability through the multiple use of a product.

Practice test of the compostable bag

In Germany, more than 3 billion thin fruit and vegetable bags are used in retail outlets every year and they are mostly used only once (UBA 2022). At the same time, the misthrow of conventional plastic bags makes it difficult for composting facilities to process separately collected biowaste. The obtained compost can be of reduced quality containing plastic residues. Furthermore, this can lead to microplastic pollution in agricultural soils if the compost is used on the field. To test the multiple use of bio-based, compostable fruit and vegetable bags in practice, C.A.R.M.E.N. e.V. collaborated with grocery stores, consumers, and waste management bodies in the defined model region Straubing. Here a compostable fruit and vegetable bag was offered in the markets under the term “Bio-Beutel / bio-bag”. They are an innovative bio-based, compostable product based on renewable raw materials. The compostable bag is suitable for the use as transport packaging, keep-fresh bag for food, and as a collection bag for organic kitchen waste. It conserves fossil, finite resources and promotes natural material cycles. The “bio-bag” was provided free of charge at the self-service counters of the four participating EDEKA and REWE retail stores in Straubing.

The labelling of the bag with the Seedling logo was correctly interpreted by most of the respondents. The majority of the surveyed also clearly recognized that the compostable bag can be used for hygienic collection and disposal of biowaste. Even though the compostable bag was predominantly identified as easily distinguishable from conventional plastic bags due to its design and the information printed on it, some participants still wished for even clearer labelling, e.g., through a more conspicuous colour scheme. According to the polls, the majority would be willing to pay a low cent amount, nevertheless many would prefer a free bag.

Excellent compost quality in Straubing – no adverse effects from compostable bags

In order to be able to document the volume of new bags in the biowaste collection during the project period, samples were taken from the biowaste on three different dates. One sample was taken before the test started, one during halftime, and a third at the end of the test phase. Already the first sorting showed that the majority of the Straubing residents is collecting most of its household biowaste in commercially available biowaste bags. The analysis showed that the use of bio-bags has no negative effects on the quality of the compost. The distributed bio-bags, as well as the commercially available biowaste bags, were completely degraded in the given rotting times